Process for 1-chloro-3,3,3-trifluoropropene from trifluoromethane

ABSTRACT

The present invention provides routes for making 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) from commercially available raw materials. More specifically, this invention provides routes for HCFO-1233zd from inexpensive and commercially available trifluoromethane (HFC-23).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from commonly owned U.S. ProvisionalApplication Ser. No. 61/863,725 filed 8 Aug. 2013, the disclosure ofwhich is hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention provides routes for making1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) from commerciallyavailable raw materials. More specifically, this invention providesroutes for HCFO-1233zd from inexpensive and commercially availablefluoroform, i.e., trifluoromethane (HFC-23).

BACKGROUND OF THE INVENTION

Trans 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) can be used for manyapplications including use as a refrigerant, blowing agent, solvent,cleaning agent and monomer for polymer compounds. The compounds of thepresent invention are part of a continued search for the next generationlow global warming potential materials with low environmental impact.

Many methods are known in the art for making HCFO-1233zd (trans), mostof them using three carbon starting materials which are obtained inmultiple steps. For example, U.S. Pat. Nos. 5,777,184 and 6,472,573describe the preparation of CF₃CH═CHCl from CCl₃CH₂CHCl₂ (240fa) with HFin the presence of a catalyst. Treatment of CF₃CH₂CF₂H (245fa) withhydrogen chloride at 280° C. with chromium catalyst is reported to give1233zd (trans and cis), see EP 2327680. Reaction of CF₃CH═CH₂ withchlorine and HF affords 1233zd as one of the products (WO 2008/54782A1).

All of the above processes involve three carbon starting materials whichin turn are made in multiple steps and thus there is a need to developcost effective routes which utilize commercially available rawmaterials. The present invention addresses this issue by utilizingfluoroform, CF₃H(HFC-23).

SUMMARY OF THE INVENTION

The present invention describes the preparation of HCFO-1233zd fromcommercially available fluoroform, (trifluoromethane, CF₃H, HFC-23).HFC-23 is a side product in the manufacture of Teflon® and iscommercially available in large quantities. The compound (CF₃H) is bothinexpensive and non-toxic, making it an excellent starting material forthe formation of HCFO-1233zd. In many industrial operations, HFC-23 isdiscarded by burning and the utilization of this waste material for theformation of useful compounds is highly desirable for reducing thisenvironmental impact.

HFC-23 can be converted to CF₃Cl with chlorine which can then be addedto chloro- or dichloro-ethylene compounds such as CHCl═CHCl, CH₂═CHCl,CH₂═CCl₂ to afford appropriate three carbon synthons from which 1233zdcan be obtained by either dehalogenation or dehydrochlorination. Thesereactions can be conducted in either the liquid phase or the gas phase,as depicted in reaction Schemes 1A-C, shown below:

Scheme 1:

ACF₃H(HFC-23)+Cl₂→CF₃Cl+HCl  (1)CF₃Cl+CH₂═CHCl→CF₃CH₂CHCl₂  (2)CF₃CH₂CHCl₂→CF₃CH═CHCl(HCFO-1233zd)+HCl  (3)BCF₃Cl+CHCl═CHCl→CF₃CHClCHCl₂  (4)CF₃CHClCHCl₂+Zn→CF₃CH═CHCl+ZnCl₂  (5)CCF₃Cl+CH₂═CCl₂→CF₃CH₂CCl₃  (6)CF₃CH₂CCl₃→CF₃CH═CCl₂+HCl  (7)CF₃CH═CCl₂+H₂→CF₃CH₂CHCl₂  (8)CF₃CH₂CHCl₂→CF₃CH═CHCl(HCFO-1233zd)+HCl  (9)

In Scheme 1B the addition of CF₃Cl to 1,2-dichloroethylene is followedby Zn mediated dechlorination to afford HCFO-1233zd. In Scheme 1C,addition of chlorotrifluoromethane to 1,1-dichloroethylene is followedby dehydrochlorination, and hydrogenation and dehydrohalogenation toafford CF₃CH═CHCl.

This starting material may generically be depicted as CHX═CYZ, where X═Hor Cl, Y═H or Cl, and Z═H or Cl.

Also, CH₂═CH₂ can be used instead of the above chloroethylenes to giveCF₃CH₂CH₂Cl which can be selectively chlorinated to CF₃CH₂CHCl₂ anddehydrochlorinated to give HCFO-1233zd, as follows:CF₃Cl+CH₂═CH₂→CF₃CH₂CH₂Cl→CF₃CH₂CHCl₂→CF₃CCH═CHCl  (10)

Fluoroform (CF₃H) can also be converted directly into HCFO-1233zd whenreacted with an appropriate catalyst at an elevated temperature. Forexample, when a mixture CF₃H and 1,2-dichloroethylene (trans/cis) ispassed over a catalyst such as Cu/CuI impregnated activated carboncatalyst, the product CF₃CH═CHCl (HCFO-1233zd) was obtained, as depictedin the following reaction scheme.

The C/Cu catalyst is made by impregnating nanocopper particles onactivated carbon pellets or granular carbon. Copper nanoparticles wereimpregnated on activated carbon by refluxing CuI in absolute ethanol andappropriate carbon (pellet/granular); the resultant Cu-impregnatedcarbon is decanted, washed with ethanol and dried for 12 hours at 100°to 200° C. prior to use.

It should be appreciated by those persons having ordinary skill in theart(s) to which the present invention relates that any of the featuresdescribed herein in respect of any particular aspect and/or embodimentof the present invention can be combined with one or more of any of theother features of any other aspects and/or embodiments of the presentinvention described herein, with modifications as appropriate to ensurecompatibility of the combinations. Such combinations are considered tobe part of the present invention contemplated by this disclosure.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention as claimed. Other embodimentswill be apparent to those skilled in the art from consideration of thespecification and practice of the invention disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

As set forth above, the present invention provides synthetic routes formaking 1-chloro-3,3,3-trifluoroprop ene (HCFO-1233 zd) from aninexpensive and commercially available compound, trifluoromethane(HFC-23).

Accordingly, one embodiment of the invention is directed to a processfor the formation of 1-chloro-3,3,3-trifluoropropene from CF₃H(HFC-23)selected from the group of reactions consisting of:

(a) the catalytic reaction of 1,2-dichloroethylene with CF₃H at atemperature of from 350° to 400° C.;

(b) a reaction comprising the steps of:

-   -   (i) the chlorination of CF₃H to form CF₃Cl;    -   (ii) the reaction of CF₃Cl with one or more chloroethylene        compounds to form one or more chlorofluorocarbon three carbon        synthon compounds; and    -   (iii) the conversion of the three carbon synthon compounds to        CF₃CH═CHCl; and

(c) a combination of reactions (a) and (b).

In certain embodiments, the chloroethylene compounds are selected fromthe group consisting of 1-chloroethylene, 1,1-dichloroethylene and1,2-dichloroethylene and mixtures of two or more.

In certain embodiments, the chloroethylene compound comprises1-chloroethylene.

In certain embodiments, the chloroethylene compound comprises1,1-dichloroethylene.

In certain embodiments, the chloroethylene compound comprises1,2-dichloroethylene.

In certain embodiments, the three carbon synthon compounds are selectedfrom the group consisting of 1,1-dichloro-3,3,3-trifluoropropane,1,1-dichloro-2-chloro-3,3,3-trifluoropropane,1,1,1-trichloro-3,3,3-trifluoropropane, and mixtures of two or more ofthese compounds.

In certain embodiments the three carbon synthon compound comprises1,1-dichloro-3,3,3-trifluoropropane.

In certain embodiments the three carbon synthon compound comprises1,1-dichloro-2-chloro-3,3,3-trifluoropropane.

In certain embodiments the three carbon synthon compound comprises1,1,1-trichloro-3,3,3-trifluoropropane.

Another embodiment of the invention is directed to a process for theformation of 1-chloro-3,3,3-trifluoropropene comprising the catalyticreaction of 1,2-dichloroethylene with CF₃H at a temperature of from 350°to 400° C.

Yet another embodiment of the invention is directed to a process for theformation of 1-chloro-3,3,3-trifluoropropene from CF₃H(HFC-23)comprising the steps of:

(a) the chlorination of CF₃H to form CF₃Cl;

(b) the reaction of CF₃Cl with one or more chloroethylene compounds toform one or more chlorofluorocarbon three carbon synthon compounds; and

(c) the conversion of the three carbon synthon compounds to CF₃CH═CHCl.

In certain embodiments the chloroethylene compounds are selected fromthe group consisting of 1-chloroethylene, 1,1-dichloroethylene and1,2-dichloroethylene, and mixtures of two or more.

In certain embodiments, the chloroethylene compound comprises1-chloroethylene.

In certain embodiments, the chloroethylene compound comprises1,1-dichloroethylene.

In certain embodiments, the chloroethylene compound comprises1,2-dichloroethylene.

In certain embodiments, the three carbon synthon compounds are selectedfrom the group consisting of 1,1-dichloro-3,3,3-trifluoropropane,1,1,2-trichloro-3,3,3-trifluoropropane,1,1,1-trichloro-3,3,3-trifluoropropane, and mixtures of two or more.

In certain embodiments, the three carbon synthon compound comprises1,1-dichloro-3,3,3-trifluoropropane.

In certain embodiments, the three carbon synthon compound comprises1,1,2-trichloro-3,3,3-trifluoropropane.

In certain embodiments, the three carbon synthon compound comprises1,1,1-trichloro-3,3,3-trifluoropropane.

In general, it is possible that certain reactions employed herein can becarried out in the liquid or in the gas phase, or in a combination ofgas and liquid phases, and it is contemplated that the reactions can becarried out batch wise, continuous, or a combination of these.

Preferably the reactor vessel is comprised of materials which areresistant to corrosion as Hastelloy, Inconel, Monel and/orfluoropolymers linings.

In certain embodiments, the reactor vessel contains catalyst, forexample a fixed or fluid catalyst bed, packed with a suitable catalyst,with suitable means to ensure that the reaction mixture is maintainedwith the desired reaction temperature range.

In general it is also contemplated that a wide variety of reactionpressures may be used for the reactions, depending again on relevantfactors such as the specific catalyst being used. The reaction pressurecan be, for example, superatmospheric, atmospheric or under vacuum andin certain preferred embodiments is from about 1 to about 200 psia, andin certain embodiments from about 1 to about 120 psia.

In certain embodiments, an inert diluent gas, such as nitrogen, may beused in combination with the other reactor feed(s).

It is contemplated that the amount of catalyst use will vary dependingon the particular parameters present in each embodiment.

The following examples provide additional details regarding variousembodiments of the present invention. However, the present invention isnot limited to the following examples.

EXAMPLES Example 1 Reaction of CF₃H with CHCl═CHCl

Catalyst Preparation:

Activated carbon (Shirasagai or Aldrich) was refluxed with 5 M nitricacid (in the ratio 1 g/25 mL) for 4 hours, decanted, washed withde-ionized water until the pH of the washing became 7.0 and was thendried under vacuum for 12 hours. Then activated carbon with copperiodide in absolute ethanol (ratio of activated C:CuI:Ethanol=1:0.1:30)was refluxed for 4 hours, washed with 4×30 mL ethanol and dried at 110°C. for overnight prior to use.

A stainless steel tube (0.5 inch×14 inches) was loaded with 25 cccatalyst (Activated Shirasagai Carbon pellet impregnated with Cu/CuInanoparticles) and heated to and maintained at 200° C. under a nitrogenpurge (20 sccm). Then the temperature was raised to 350° C. and amixture of CF₃H and CHCl═CHCl was passed over it with a contact time offrom 10 to 60 seconds. The exit stream from the reactor was analyzed byGC and GC-MS. The percentage of CF₃CH═CHCl in the exit stream rangedfrom 20% to 30%.

Example 2 Conversion of CF₃H to CF₃Cl

A Monel tube reactor (0.5 inch×14 inches) was packed with 25 cm³activated carbon (granular, 4-14 mesh) and purged with nitrogen at 150°to 200° C. for one hour. The tube reactor was heated to and maintainedat 300° C. and a mixture of CF₃H(HFC-23) and chlorine (in the ratio 1:3)was passed through the reactor in such way that the contact time wasbetween 15 to 20 seconds. The product mixture in the exit stream waspassed through a 10% aq. KOH solution and over CaSO₄ column; CF₃Cl(HFC-13) was collected in a cylinder cooled by liquid nitrogen.

Typical yields ranged from 80% to 90%. The chlorination of CF₃H was alsodone with other types of activated carbon such as Calgon or Shirasagaigranular to give the CF₃Cl.

Example 3 Addition of CF₃Cl to CH₂═CHCl

Into a 350 mL capacity Hastelloy C autoclave awes added ferric chloride(1.0 g), iron powder (0.2 g) and tributylphosphate (2.75 g). Theautoclave was then purged with nitrogen, and pressurized/charged withCF₃Cl (2.57 mol, 267 g) and then heated to a temperature of from 115° to120° C. Then vinyl chloride was charged intermittently into theautoclave with constant stirring; as the addition takes place thepressure decreases and more CH₂═CHCl was fed into the reactor. Totalamount added was 167 g (2.7 mol). The product CF₃CH₂CHCl₂ was separatedand distilled to afford 350 g (yield=82%).

Example 4 Addition of CF₃Cl to CHCl═CHCl

This reaction was conducted exactly the same manner as in Example 3except for the fact that CH₂═CHCl was substituted by1,2-dichloroethylene (trans/cis) CHCl═CHCl. The yield of CF₃CHClCHCl₂ranged from 50% to 70%.

Example 5

This reaction was conducted exactly in the same manner as Example 3,except that CH₂═CHCl was substituted by 1,1-dichloroethylene CH₂═CCl₂ orCH₂═CH₂ to afford 65% CF₃CH₂CCl₃ or CF₃CH₂CH₂Cl (60%), respectively

Example 6 Conversion of CF₃CH₂CHCl₂ to CF₃CH═CHCl (HCFO-1233zd) Step (A)Liquid Phase

To a 25% aq. KOH solution containing 2% Aliquat 336 by weight was heatedto and maintained at 40° C. CF₃CH₂CHCl₂ was added drop-wise over aperiod of 1 hour; the product was collected in cold trap (−78° C., dryice/IPA). The molar ratio of KOH to CF₃CH₂CHCl₂ was 1:1 equivalent. Theyields of HCFO-1233zd ranged from 80% to 90%.

Step (B) Vapor Phase

A stainless steel tubular reactor was charged with 25 cc fluorinatedCr₂O₃ catalyst. Then the reactor tube was heated under purge of nitrogento 400° C. Nitrogen flow was stopped and CF₃CHCHCl₂ was fed at a flowrate of from 0.2 to 0.5 cc/min which was fed to a vaporizer and then tothe tubular reactor; the exit stream contained mainly HCFO-1233zd, at ayield greater than 80%, in addition to some unreacted starting material.

Example 7 Conversion CF₃CH₂CCl₃ to CF₃CH═CCl₂

This reaction was conducted essentially the same manner as described inExample 6 in liquid and vapor phases; the yields ranged between 50-70%.

Example 8 Hydrogenation of CF₃CH═CCl₂ to CF₃CH₂CHCl₂

Into a 1 L stainless steel autoclave was added 1 g of hydrogenationcatalyst (about 2% Pd on C), and 200 mL methanol under a nitrogen purge.The autoclave was sealed, cooled to −20° C. and evacuated to removeexcess nitrogen; then 0.40 mol of CF₃CH═CCl₂ was added. Then autoclavewas brought to about 0° C. and slowly charged with 0.4 mol H₂; thereaction mixture was stirred continuously and the pressure drop wasmonitored over time. The reaction was stopped once there was no pressurechange over a period of 1 hour. The product, mainly CF₃CH₂CHCl₂, wasdistilled off from the reactor (0.30 mol, 75% yield).

Example 9 Conversion of CF₃CHClCHCl₂ to CF₃CH═CHCl

To a stirred mixture of Zn powder (activated with acetic acid/aceticanhydride) (14.4 g, 0.21 mol) and dry methanol (25 mL) was addedCF₃CHClCH₂Cl (0.10 mol) drop-wise with an addition funnel at from 50° to55° C. over a period of 2 hours. The volatile material formed from thereaction was collected in a cold trap to afford 60% yield of CF₃CH═CHCl.

As used herein, the singular forms “a”, “an” and “the” include pluralunless the context clearly dictates otherwise. Moreover, when an amount,concentration, or other value or parameter is given as either a range,preferred range, or a list of upper preferable values and lowerpreferable values, this is to be understood as specifically disclosingall ranges formed from any pair of any upper range limit or preferredvalue and any lower range limit or preferred value, regardless ofwhether ranges are separately disclosed. Where a range of numericalvalues is recited herein, unless otherwise stated, the range is intendedto include the endpoints thereof, and all integers and fractions withinthe range. It is not intended that the scope of the invention be limitedto the specific values recited when defining a range.

It should be understood that the foregoing description is onlyillustrative of the present invention. Various alternatives andmodifications can be devised by those skilled in the art withoutdeparting from the invention. Accordingly, the present invention isintended to embrace all such alternatives, modifications and variancesthat fall within the scope of the appended claims.

What is claimed is:
 1. A process for the formation of1-chloro-3,3,3-trifluoropropene from CF₃H (HFC-23) comprising thecatalytic reaction of 1,2-dichloroethylene with CF₃H at a temperature offrom 350° C. to 400° C.
 2. A process for the formation of1-chloro-3,3,3-trifluoropropene from CF₃H (HFC-23) comprising the stepsof: (i) the chlorination of CF₃H to form CF₃Cl; (ii) the reaction ofCF₃Cl with one or more chloroethylene compounds to form one or morechlorofluorocarbon three carbon synthon compounds; and (iii) theconversion of the three carbon synthon compounds to CF₃CH═CHCl.
 3. Theprocess of claim 2, wherein the chloroethylene compounds are selectedfrom the group consisting of 1-chloroethylene, 1,1-dichloroethylene and1,2-dichloroethylene and mixtures of two or more.
 4. The process ofclaim 2, wherein the chloroethylene compound comprises 1-chloroethylene.5. The process of claim 2, wherein the chloroethylene compound comprises1,1-dichloroethylene.
 6. The process of claim 2, wherein thechloroethylene compound comprises 1,2-dichloroethylene.
 7. The processof claim 2, wherein the three carbon synthon compounds are selected fromthe group consisting of 1,1-dichloro-3,3,3-trifluoropropane,1,1-dichloro-2-chloro-3,3,3-trifluoropropane,1,1,1-trichloro-3,3,3-trifluoropropane, and mixtures of two or more. 8.The process of claim 2, wherein the three carbon synthon compoundcomprises 1,1-dichloro-3,3,3-trifluoropropane.
 9. The process of claim2, wherein the three carbon synthon compound comprises1,1-dichloro-2-chloro-3,3,3-trifluoropropane.
 10. The process of claim2, wherein the three carbon synthon compound comprises1,1,1-trichloro-3,3,3-trifluoropropane.
 11. A process for the formationof 2-chloro-3,3,3-trifluoropropene comprising the catalytic reaction of1,2-dichloroethylene with CF₃H at a temperature of from 350° to 400° C.12. A process for the formation of 1-chloro-3,3,3-trifluoropropene fromCF₃H (HFC-23) comprising the steps of: (i) the chlorination of CF₃H toform CF₃Cl; (ii) the reaction of CF₃Cl with CH₂═CH₂ to form the compoundCF₃CH₂CH₂Cl; (iii) the selective chlorination of CF₃CH₂CH₂Cl to form thecompound CF₃CH₂CHCl₂; and (iv) the dehydrochlorination of CF₃CH₂CHCl₂into CF₃CH═CHCl.